Which Is The Best Thermos Flask For Sale In The UK?

Check out our best rated items in 2021.

Best Pick Thermos Flask: Our Review Score = 98%

Best Overall
Thermos 104110 Ultimate Series Flask, Charcoal, 900 ml
  • Thermos vacuum insulation technology for maximum...
  • Stainless steel interior and exterior featuring...
  • Cool to the touch with hot liquids, sweat-proof with...
  • Two part stopper to smooth the flow of liquids

Top Rated Thermos Flask: Highest Customer Review Score

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Thermos Stainless King Flask, Midnight Blue, 1.2 L, 183267
  • Thermos vacuum insulation technology for maximum...
  • Durable stainless steel interior and exterior with...
  • Cool to the touch with hot liquids and sweat-proof with...
  • Twist and pour stopper allows you to pour without...

Best Cheap Thermos Flask: Great Value

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Thermos 187011 ThermoCafé Stainless Steel Flask, Hammertone Grey, 500 ml
  • Double wall vacuum insulation retains hot or cold...
  • Durable stainless steel interior and exterior
  • Cool to the touch with hot liquids, sweat-proof with...
  • Insulated stainless steel serving cup

How To Choose A Thermos Flask ( 2021 Buying Guide)

Thermos flasks have come a long way since the days of parents and grandparents carting tea about in discoloured plastic versions to avoid buying a cuppa on a day out, but the concept is still the same: keep hot things hot, and cold things cold. Whether you’re taking a salad in to the office, carting soup on a hike, or just need to keep your coffee hot on the commute, there’s a thermos flask to do the job. So how to choose the right one?

What type?

There’s a staggering variety of thermos flasks on offer these days, so decide what you’re most likely to use it for. If you’re simply looking for something to keep your tea warm on a cold day or in the car, there are plenty of beverage mugs with opening lids that allow you to drink on the go. You’ll find ones styled after takeaway coffee cups, as well as others shaped to fit car cup holders and equipped with handles, so there’s sure to be one to suit your needs.

But maybe you’re after something for the kids’ lunchboxes, or your own. Thermos flasks more suited for food will have wider lids to allow easy access, and some will even have separate compartments to allow you to keep your soup hot in one, while the fruit stays cool in another.

Or perhaps you’re simply after a large thermos flask that can carry enough hot chocolate to warm up the whole family mid-hike. There are plenty of more traditional flasks available, with or without pouring spouts to make serving easier.


As mentioned before, perhaps you have a group to serve, in which case you’ll be looking for 1L or larger. However, flasks of this size are bulky, and far less suited for daily use at home of the office. Additionally, the thermos works best when full, as the additional air present inside when the flask is only partially filled conducts heat away from the contents more quickly, so you may find your tea doesn’t stay hot long if you’re using too big a container.


Thermos flasks are primarily constructed of either stainless steel or plastic these days, although glass ones can still be found. While glass interiors are very hygienic, and won’t retain the taste of the contents, they are less robust, and may not stand up to hard use such as hiking. Plastic, while resilient, is prone to retaining the taste of the contents – not too much of a problem if you’re using your flask just for coffee, but less appealing if you’re using it for a mix of tea, soup, and other items. Stainless steel is both hygienic and strong, and most good thermos flasks these days are constructed with it.

Thermal properties

Consider how long you need the contents to stay hot (or cold) for. While a basic insulated food flask will keep your soup warm until lunchtime, it probably won’t stay hot to be enjoyed at the end of an eight-hour hike. Conversely, your heavily insulated flask may keep your coffee piping to be enjoyed at the end of that same hike, it’s going to take a long time to get to drinking temperature at work.

Finally, check the reviews of the product you’re planning to buy, and, if possible, inspect it closely to make sure that the lid seems to seal well and that it doesn’t seem to bulky or awkward for your needs.